Researchers at the University of Washington in Seattle are building the first mobile devices to effectively transmit American Sign Language via compressed video over a 3G cellular network.

The problem they are trying to solve is optimizing the compressed video for sign language so that it can be transmitted on a 3G network, instead of requiring faster 4G network speeds, according to a report published on the university's Web site. The engineers have increased image quality around faces and hands used in ASL while still delivering intelligible sign language via video at speeds of 30Kbit/sec.

The engineers on the project are finishing a three-week initial trial of the MobileASL tool on older phones equipped with cameras for video chat, although the software is designed to work on a range of smartphones and other mobile devices.

The field test was conducted with the help of 11 students in a UW summer academy for people who are deaf or hard of hearing and are interested in computing careers. They made 200 calls with the MobileASL software, each averaging 90 seconds, and got generally positive results.

The MobileASL "is good for fast communication," reported Tong Song, a student at Gallaudet University in Washington and one of the study volunteers. Students in the study said texting and e-mail are often too slow.

UW engineers estimate that MobileASL will use one-tenth the bandwidth of the iPhone 4's FaceTime videoconferencing application. MobileASL could work with the iPhone 4 and other smartphones with a front-facing camera.

Eve Riskin, a UW professor of electrical engineering, said the study was the first to assess how deaf people in the U.S. use video phones. Even if a user of MobileASL has access to 4G wireless, the software will help extend battery life and eventually lower costs, the researchers said.

The field study was headed by Jessica Tran, a doctoral student in electrical engineering. Jaehong Chon, another doctoral student, adapted MobileASL to the H.264 video compression standard. The study also involved Tressa Johnson, an ASL interpreter who is working toward a master's degree in library and information science and is studying MobileASL's impact on the deaf community.